Shell and tube heat exchangers typically include headers on each end of the shell in order to provide access to the tubes within the shell for cleaning or service. The headers also provide containment for refrigerant or heat exchange fluid and provide the refrigerant or heat exchange fluid to the tubes. Chiller systems typically include a chiller heat exchanger, which is a shell and tube heat exchanger having a refrigerant flow in the tubes and heat exchange fluid, such as water, flowing in the shell. Each end of the chiller heat exchanger includes a header fastened to the shell. The header includes a flat head plate and a baffle chamber. The head plate is a flat, thick plate that provides containment of the refrigerant within the system. A gasket is placed between the head plate and the baffle chamber in order to reduce leakage. The baffle chamber contains one or more baffles to direct the flow of refrigerant into the tubes of the shell. The baffles also substantially prevent leakage between the inlet and outlet. A second gasket is placed between the baffle chamber and the shell in order to reduce leakage. Chiller systems may also include multiple refrigerant circuits having refrigerant loops that are independent of each other. In systems having multiple circuits, a divider between the circuits must also be included in the baffle chamber and independently attached. The divider requires bolts that fasten the divider to the end of the shell, adding to the complexity of installation, requiring additional gaskets, reducing the area available for tubes within the shell, and causing additional stress on the bolts fastening the header to the shell. These chiller heat exchangers have the additional drawback that multiple gaskets are required, thus increasing the occurrences of leakage of refrigerant and increasing the service costs. These chiller heat exchangers have the further drawback that the flat plate on the header is relatively thick and heavy, thereby increasing material cost and weight of the system. Additional bolts positioned at the center of the flat head, referred to as center bolts, are required on the flat heads to try to minimize deflection and avoid excessively thick heads. However, these center bolts are generally overstressed and result in additional leakage paths and cost.
Therefore, what is needed is a header assembly that contains refrigerant, requires simpler gasketing, weighs less, costs less, provides reduced stress for the fasteners attaching the head to the heat exchanger, provides high velocity refrigerant flow, and high efficiency operation, and eliminates the center bolts.